Prostate cancer is the most common malignancy and the second leading cause of cancer death in men in the United States (Jemal A, et al., CA Cancer J Clin 2005; 55:10-30). Localized prostate cancer typically is treated with surgery or radiation, and recurrent disease can be controlled temporarily with androgen ablation (Klein E A, et al., Urol Clin North Am 2003; 30:315-30). However, almost all prostate carcinomas eventually become hormone refractory and then rapidly progress (Denmeade S R, et al., Nat Rev Cancer 2002; 2:389-96). Hormone-refractory or androgen-independent prostate cancer has proven to be largely resistant to conventional chemotherapy. With the exception of palliative care, the only approved chemotherapy is docetaxel in combination with prednisone, which offers a modest (2.4 month) survival benefit (Gulley J, et al., Am J Ther. 2004; 351:1513-20; Petrylak D P, et al., New Engl J Med 2004; 351:1513-20).